Expansion of Heathrow, Gatwick and Stansted

For: the government’s three main airports will be full by 2030 and Heathrow is already near to capacity. Expansion would provide a significant economic boost, estimated at £7bn a year at Heathrow alone, and help Britain to remain internationally competitive.

Against: people living near all three airports say expansion goes against the pledges by successive governments to tackle global warming. They also say quality of life will be shattered by new flight paths.

Thames Estuary

For: could carry up to 150m passengers a year. Boris Johnson believes it could be built in as little as six years and that sovereign wealth funds would be willing to stump up the cost of construction.

Against: a host of engineering challenges to be overcome and it would pose a severe threat to local birdlife. Planners would also have to work out how to remove the wreck of SS Richard Montgomery, a US warship sunk during the Second World War and still stocked with explosives. The airport is likely to be opposed by the Lib Dems.


For: airport hub would enable passengers to travel between Heathrow and Gatwick in just 15 minutes via high-speed rail, reinforcing London’s reputation as a centre for global travel.

Against: The scheme could cost £5bn and it faces “very significant” challenges according to Willie Walsh, chief executive of International Airline Group, which owns British Airways.